LED Bonding Electrode Double-Platform Design for Yield
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Solution Overview
Problem
The bonding process for micro light-emitting diodes (μLEDs) faces challenges due to their small size, leading to poor contact and low yield, as existing methods struggle to achieve high bonding efficiency with current materials and techniques.
Innovation Solution
A light-emitting diode structure featuring a mesa structure with contact electrodes, an insulating layer, and bonding electrodes with a double-layer terrace design, where the second platform is more bulged out and has a smaller surface area, allowing easier penetration through the adhesive layer and improved electrical contact without reducing the light emission area, along with a mirror surface conducting layer for enhanced current spreading and light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical pressure is used to pass μLED through the adhesive layer, then bonding is achieved, but contact quality is poor and yield is low
Solution Approach 1:
The bonding electrode is divided into two platforms: a first platform for initial contact and a second platform for final bonding. This segmentation allows the bonding process to occur in stages, first establishing electrical contact and then achieving mechanical bonding, thereby resolving the contradiction between bonding yield and contact quality.
Solution Approach 2:
The invention introduces a vertical dimension to the bonding process by creating a stepped structure with two platforms at different heights. The first platform engages the adhesive layer at a lower level while the second platform provides a higher contact surface, adding dimensional complexity to improve both bonding reliability and contact precision.
2Reliability
If the bonding electrode surface area is reduced to penetrate adhesive layer easier, then bonding yield improves, but electrical contact area may be insufficient
Solution Approach 1:
The bonding electrode is segmented into two platforms with different surface areas. The first platform has a larger surface area to ensure adequate electrical contact, while the second platform has a smaller surface area to facilitate penetration through the adhesive layer. This segmentation resolves the contradiction between bonding yield and electrical contact area.
Solution Approach 2:
Different regions of the bonding electrode are given different qualities: the first platform provides a larger contact area for electrical connection, while the second platform provides a smaller, more concentrated area for mechanical penetration. This local differentiation of properties allows the electrode to simultaneously satisfy both requirements.
Data Source
AI summary
A light-emitting diode structure for improving bonding yield is provided, which includes a light-emitting diode, a plurality of contact electrodes, an insulating layer structure, and a plurality of bonding electrodes. One surface of the light-emitting diode includes a mesa structure. The contact electrodes are on the mesa structure. The bonding electrodes are on the insulating layer structure and respectively cover at least one contact electrode. A surface of one of the bonding electrodes facing away from the light-emitting diode has a first platform and a second platform. The second platform is on the first platform. A surface area of a vertical projection of the second platform on the light-emitting diode is smaller than that of the first platform on the light-emitting diode, and said vertical projection of the second platform is within that of the first platform.